| 释义 |
hemixis Biol.|hɛˈmɪksɪs|
Also hemimixis.
[f. hemi- + Gr. µίξις mixing, f. µ(ε)ίγνυµι to mix: see mixo-.]
In Paramecium, any of several types of change in the macronucleus, such as fission or elimination of chromatin, which take place without involving the micronucleus. So heˈmictic a., of, pertaining to, or characterized by hemixis.
1936W. F. Diller in Jrnl. Morphol. LIX. 18 The attempt at interpreting the varied cytological conditions which P. aurelia exhibits under different circumstances has led to the discovery of a hitherto undescribed sexual reproductive process which corresponds to autogamy as it is known in other animals, and to a group of asexual phenomena which will be called ‘hemixis’. Ibid. 36 It is proposed to group these reorganizations together..and refer to them collectively by the term ‘hemixis’. By this term is meant a series of autonomous changes which the macronucleus undergoes in vegetative life, exclusive of binary fission. Ibid., No genetic relationships are necessarily implied between the varieties of hemictic phenomena. 1940L. H. Hyman Invertebrates I. iii. 176 In hemimixis the macronucleus undergoes degenerative changes. 1953R. Wichterman Biol. Paramecium iii. 90/2 Hemictic animals with the two micronuclei may show variable numbers and sizes of macronuclear fragments. 1961Mackinnon & Hawes Introd. Study Protozoa iv. 292 A variety of nuclear changes may occur [in Paramecium] without the intervention of a micronucleus; they are collectively known as hemixis..and their significance is uncertain. |